And despite their lower level of protection, there's strong evidence that flu vaccines do protect lupus patients from the flu.

Albert Holvast, MD, of the University of Groningen, Netherlands, and colleagues looked at anti-flu immune responses in 54 lupus patients and 54 healthy patients.

Previous studies have shown that lupus patients make fewer protective antibodies after flu vaccination. The new study shows that another arm of the immune system, cell-mediated immunity, also responds less well to flu vaccination in lupus patients.

"Evaluation of clinical protection against influenza in patients with SLE following influenza vaccination seems indicated in order to assess whether more effective influenza vaccines, or vaccination strategies, are warranted."

Immune-boosting substances called adjuvants are being developed to increase the depth and breadth of the immune responses elicited by vaccines. None of these adjuvants has been approved in the U.S., although some of the products are used in Europe.

Holvast and colleagues report their findings in the August issue of Arthritis & Rheumatism.